Glass globe and reflector.



0 S Q r 0 WITNESSES INVENTOH v BY r ATTORNEYS OTIS A.

mraa'rir, am 101m, N. Y.

cuss cross annnnrnscros.

Specification of Iietters Patent.

Patent ed Sept. 22, 1914.

- Application flied Tune 1908. Serial No. 436,868.

To all whom it may concern:

Be it known that I, OTIS A. Mroxrr, a

citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful. Improvements in Glass Globes and Reflectors,of which the follow- .ing is a specification, referencebeing'had therein to the accompanying drawing.

The object of the invention is to provide prism glass, globes, shades and reflectors having their outer surfaces practically covered with radial ribs, so that such shades "will appear over most of their surface com-- posed of'the same medium, while different parts oftheir surface will act diiferentlyon light rays:

All prism glass shades so far constructedhave been of two types: The first type are homogeneous in appearance, practically their entire surface being covered with sub vst'antially radial prisms. In the second their length,a 90 degreeprism being a 90 degree prism from top to bottom, and an 80 degree prism being an 80 degree prism from top to bottom: Each part of the prism therefore is of the same mechanical reflecting power or light directing power, and a shade made of a definite shape would necessarily have to give a definitelight distributing result.

Experience in making hundreds of thousands of prismatic shades has shown me that a. homogeneous shade ofthe proper shape, that is a shade having substantially radial prisms from top to bottom, is the one that pleases most by its a pearance; nevertheless, the limitation in ight distributing power of such shades have been a. great drawback. I attempted to overcome this in a shade of the second type mentioned, exemplified in my Patent No. 821,306, but at the cost of destroyingthe general evenness or homogeneousness of the appearance of the reflector. In that Patent I disclose interrupted reflecting risms which allow the light to pass throng 1 and out of the reflector, and so modify its reflecting light distributing power. Reflectors made under my Patent No. 821,306 are in practice very efiicient from a scientific standpoint, because by means of this invention a. reflector made of definite shape can be made to give many different light distributions by mutilating or interrupting the prisms, to permit the light .to pass through and out. In practice, however, they have often failed to satisfy decorative tastes because they are not homogeneous in appearance, the interruption or mutilation of the radial prisms always producing a design; so that although the distribution of light may be satisfactory, the appearance of the reflector is not necessarily so. My present invention is intended to give to prism glass shades and reflectors having substantially radial prisms on their surface all the'flexibility of light distribution given by my Patent No. 821,306, without alterin the general appearance of, the reflector. t is a well known fact that a shade or reflector having on its outer surface substantially radial prisms of about 90 degrees will reflect back most of the rays of light striking the surface. If the angle of these prisms should be altered, its quality as a good reflector diminishes until somewhere between 100 and 110 degrees, itceases to have any reflecting power whatever and becomes simly a Pl'lSlIl which transmits or directs ht to theeye However, a. radial prism on a glass shade looks practically the same, whether it is 90, 100 or even 110 degrees. I make use of this fact to produce reflectors of homogeneous appearance, which are apparently substantially covered from top to ttom with substantially similar radial prisms; yet by making the molds in such a way that the angle of this prism is changed in difi'erent parts of its length, I 8.1114311- abled to produce shades and reflectors of exactly the same size, sha and appear ance, which have totally di erent light distributing curves or light distributing power. For instance, two deep shaped reflectors can be made exactly similar in size, shape and general a pearance, with exactly the same types of light source laced inside and in exactly the same position, and still one reflector manufactured under this present application will 1give a concentrating curve of reflection, wh' e the other will give a socalled bats wing curve of distribution.

' Figure 1 is a side elevation of a shade embodying my invention, a partof the shade only being shown covered with prisms as a matter of convenience; Fig. 2 is another elevation of a globe-embodying the invention. Fig. 3 is an elevation of another form of shade embodying the invention. Fig. .4 is a vertical cross section-of a mold and plunger indicating the variations of the cutting angles. Fig. 5 is a series of crosssections showing the prism angles of Fig. 4. In Fig. 1 the upper risms from A to B are here shown as 120. egrees for transmission, while the lower prisms from B.to C are shown as QOdegrees for reflection. The transmission may be gradual if desired. This is of course all-carried out in an integral prism, which is apparently homogeneous.

In Fig. 2, :thelight-rays sent from the light source to the 90 degree prisms, in this instance at the top of the globe, are totally reflected bythese prisms and then transmitted through the transmitting prisms of 110. The prisms have an integral honiogneous appearance never achieved by an own type of globe, in conjunction wit the'various fimctionswhich are set forth in this invention.

In Fig. 5 at H the angles are shown as 90' degrees, at 31-3 they areshown as '120 degrees and at aa they are shown as 150 degrees.-- v

For producing commercial reflectorssimilar in appearance, size and shafiei my invention ismost important in enab exie abso.

lutely: to control the light -distributing curvesgiven by almost any sire and shape of reflector without changing its a pear' anus. Very often in a lar e room di erent light means used in di erent' parts will need different curves of light distribution;

'claim is:

'et' for uniformity all such reflectors should of the same size, shape and ap from a decorative standpoint. 'therto where reflectors were made of the same reflecting medium, and of the same size, sha e and. appearance they have always given t e same curve of light distribution. t'is only by my present invention that two prismatic reflectors identical in appearance, size, shape and'type' can be made which will give two totally different curves of light distribution. I accomplish this by altering the angle of the prisms used on my shade in different parts of their lengths, so that although the reflector appears homogeneous over its entire surface, being apparently substantially covered with similar substantially radial risms, nevertheless in fact it.

is of totally dlfi'erent reflectin power in different parts of its surface. uch parts are arranged at will accordin to the curve of light distribution require by simply flat tenin out more or les the prism in difparts of its length, in order to control. thetotal light reflected from different areas of the shade or reflector. A difl'erence of less than 20 degrees inthe angle of a radial prism on a shade .will change it from re-. ,flecting back over 80% of the light to transinitting over 80%of the light.

Having described my invention, what I Transparent glass shades having substantially radial prisms running light reflection from definite parts of its ielfih and light transmission through other de ite parts of its len h.

0 IS A.'MYGATT. Witnesses:

W. A. Dorsey, Jon. B. LIBERMAN.

. pra'ctit lly from top to bottom of the shade, the angle of each of said prisms gradually-varying -in. definite parts of its length so as to allow 

